Implantable stimulation device for snoring treatment

ABSTRACT

The present disclosure relates to methods and apparatuses for treating snoring by implanting a stimulating electrode into a patient. The electrode is placed in stimulating contact with an airway passage-controlling muscle of the patient. The electrode is energized to contract the muscle and alter the airway passage.

BACKGROUND

[0001] 1. Field of the Invention

[0002] This invention is directed to method and apparatus for treatingsnoring.

[0003] 2. Description of the Prior Art

[0004] Snoring has received increased scientific and academic attention.One publication estimates that up to 20% of the adult population snoreshabitually. Huang, et al., “Biomechanics of Snoring”, Endeavour, Vol.19, No. 3, pp. 96-100 (1995). Snoring can be a serious cause of maritaldiscord. In addition, snoring can present a serious health risk to thesnorer. In 10% of habitual snorers, collapse of the airway during sleepcan lead to obstructive sleep apnea syndrome. Id.

[0005] Notwithstanding numerous efforts to address snoring, effectivetreatment of snoring has been elusive. Such treatment may include mouthguards or other appliances worn by the snorer during sleep. However,patients find such appliances uncomfortable and frequently discontinueuse (presumably adding to marital stress).

[0006] Surgical treatments have been employed. One such treatment isuvulopalatopharyngoplasty. In this procedure, so-called laser ablationis used to remove about 2 cm of the trailing edge of the soft palatethereby reducing the soft palate's ability to flutter between the tongueand the pharyngeal wall of the throat. The procedure is frequentlyeffective to abate snoring but is painful and frequently results inundesirable side effects. Namely, removal of the soft palate trailingedge comprises the soft palate's ability to seal off nasal passagesduring swallowing and speech. In an estimated 25% ofuvulopalatopharyngoplasty patients, fluid escapes from the mouth intothe nose while drinking. Huang, et al., supra at 99.Uvulopalatopharyngoplasty (UPPP) is also described in Harries, et al.,“The Surgical treatment of snoring”, Journal of Larvngology and Otology,pp. 1105-1106 (1996) which describes removal of up to 1.5 cm of the softpalate. Assessment of snoring treatment is discussed in Cole, et al.,“Snoring: A review and a Reassessment”, Journal of Otolaryngology, pp.303-306 (1995).

[0007] Huang, et al., supra, describe the soft palate and palatalsnoring as an oscillating system which responds to airflow over the softpalate. Resulting flutter of the soft palate (rapidly opening andclosing air passages) is a dynamic response generating sounds associatedwith snoring. Huang, et al., propose an alternative touvulopalatopharyngoplasty. The proposal includes using a surgical laserto create scar tissue on the surface of the soft palate. The scar is toreduce flexibility of the soft palate to reduce palatal flutter. Huang,et al., report initial results of complete or near-complete reduction insnoring and reduced side effects.

[0008] Surgical procedures such as uvulopalatopharyngoplasty and thoseproposed by Huang, et al., continue to have problems. The area ofsurgical treatment (i.e., removal of palatal tissue or scarring ofpalatal tissue) may be more than is necessary to treat the patient'scondition. Surgical lasers are expensive. The proposed procedures arepainful with drawn out and uncomfortable healing periods. The procedureshave complications and side effects and variable efficacy (e.g., Huang,et al., report promising results in 75% of patients suggesting a fullquarter of patients are not effectively treated after painful surgery).The procedures may involve lasting discomfort. For example, scar tissueon the soft palate may present a continuing irritant to the patient.Importantly, the procedures are not reversible in the event they happento induce adverse side effects not justified by the benefits of thesurgery.

[0009] Electrical stimulation of the soft palate has been suggested totreat snoring and obstructive sleep apnea. See, e.g., Schwartz, et al.,“Effects of electrical stimulation to the soft palate on snoring andobstructive sleep apnea”, J. Prosthetic Dentistry, pp. 273-281(1996).Devices to apply such stimulation are described in U.S. Pat. Nos.5,284,161 and 5,792,067. Such devices are appliances requiring patientadherence to a regimen of use as well as subjecting the patient todiscomfort during sleep. Alternatively, these devices must be usedduring the day for a period of time causing disruption of dailyactivity, interference with daily life. This may generally be assumed tocause them to be prone to a significant risk of non-compliance by thewearer. Such devices, though have met with some success in treatingdisorders such as snoring and Obstructive Sleep Apnea.

SUMMARY OF THE INVENTION

[0010] According to a preferred embodiment of the present invention, amethod and apparatus are disclosed for treating snoring of a patient.The invention includes implanting a stimulating electrode into apatient. The electrode is placed in stimulating contact with an airwaypassage-controlling muscle of the patient. The electrode is energized tocontract the muscle and alter the airway passage.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a side sectional view of a portion of a human headshowing a soft palate in a relaxed state and in relation in adjacentanatomical features;

[0012]FIG. 2 is a portion of the view of FIG. 1 showing the soft palatein a flexed state;

[0013]FIG. 3 is a front view of an interior of the mouth shown in FIG. 1and showing an area to be ablated according to a first prior artsurgical procedure;

[0014]FIG. 4 is the view of FIG. 3 and showing an area to be scarredaccording to a second prior art surgical procedure;

[0015]FIG. 5 is a schematic representation of a spring-mass system modelof the soft palate;

[0016]FIG. 6 is the view of FIG. 1 showing electrodes placed in themuscles of the soft palate, tongue and throat; and

[0017]FIG. 7 is a schematic representation of a pacing electrodeinductively coupled to a control device.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0018] For ease of understanding the present invention, the dynamics ofsnoring are explained with reference to FIGS. 1-5. The hard palate HPoverlies the tongue T and forms the roof of the mouth M. The hard palateHP includes a bone support B and does not materially deform duringbreathing. The soft palate SP is soft and is made up of mucous membrane,fibrous and muscle tissue extending rearward from the hard palate HP. Aleading end LE of the soft palate SP is anchored to the trailing end ofthe hard palate HP. A trailing end TE of the soft palate SP isunattached. Since the soft palate SP is not structurally supported bybone or hard cartilage, the soft palate SP droops down from the plane ofthe hard palate HP in an arcuate geometry of repose.

[0019] The pharyngeal airway passes air from the mouth M and the nasalpassages N into the trachea TR. The portion of the pharyngeal airwaydefined between opposing surfaces of the upper surface of the softpalate SP and the wall of the throat is the nasopharynx NP.

[0020] During normal breathing, the soft palate SP is in the relaxedstate shown in FIG. 1 with the nasopharynx NP unobstructed and with airfree to flow into the trachea TR from both the mouth M and the nostrilsN.

[0021] During swallowing, the soft palate SP flexes and extends (asshown in FIG. 2) to close the nasopharynx NP thereby preventing fluidflow from the mouth M to the nasal passages N. Simultaneously, theepiglottis EP closes the trachea TR so that food and drink pass onlyinto the esophagus ES and not the trachea TR. The soft palate SP is avalve to prevent regurgitation of food into the nose N. The soft palateSP also regulates airflow through the nose N while talking. Since thesoft palate SP performs such important functions, prior art techniquesfor surgically altering the soft palate SP can compromise thesefunctions.

[0022] The majority of snoring is caused by the soft palate SP flappingback and forth. If breathing is solely through the nose N with the mouthclosed, the trailing edge TE of the soft palate SP is sucked into thenasopharyngeal space NP obstructing the airway and subsequently fallsopening the airway in a repeating cycle. When the mouth is open, airflows over the upper and lower surfaces of the soft palate SP causingthe soft palate SP to flap up and down alternating in obstructing theoral and nasal passageways M, N. The snoring sound is generated byimpulses caused by rapid obstruction and opening of airways. Huang, etal., state the airway passage opening and closing occurs 50 times persecond during a snore. Huang, et al., utilizing a spring-mass model(FIG. 5) to illustrate oscillation of the soft palate in response toairflow (where the soft palate is the ball B of mass depending by aspring S from a fixed anchor A).

[0023] Huang, et al., analogize the shortening of the soft palate SP inuvulopalatopharyngoplasty as effectively raising the critical air flowspeed at which soft palate flutter will occur. The shaded area SA inFIG. 3 shows the area of the trailing end TE of the soft palate SP to beremoved during this procedure. The alternative procedure proposed byHuang, et al., reduces the flexibility of the soft palate SP throughsurface scarring which is asserted as effecting the critical flow speed.The shaded area SA′ in FIG. 4 shows the area to be scarred by thisalternate procedure. In FIG. 4, dashed line L shows the demarcationbetween the soft and hard palates.

[0024] The present invention is directed to a method and apparatus foraltering the dynamic response of the soft palate by altering airflowpast the soft palate. With reference to the spring-mass model (FIG. 5),the soft palate is moved by airflow. Airflow through an orifice variesin response to the orifice size. The present invention alters the sizeof the air passage through a minimally invasive surgical implant toallow stimulation of airway defining muscles of the oro-pharynx (i.e.,mouth and throat).

[0025] The present invention stimulates muscles of one or more of thesoft palate SP, tongue T and back of the throat. In the soft palate SP,these muscles include, but are not limited to, the Levator veli paltini,the dextera, the Palatopharyngeous and the Palatoglossus muscles. At theback of the throat, these muscles include, but are not limited to, theSuperior, Middle and Inferior pharyngeal constrictor, theSalpingopharyngeous and the Stylopharyngeous muscles. In the tongue T,these muscles include, but are not limited to, the Genioglossus andGeniohyoid muscles.

[0026] Stimulating the muscles of the soft palate, tongue and throat isintended to alter the dynamic response of the soft palate to airflow.Namely, stimulation of the soft palate SP causes the soft palate to moveaway from the tongue T, stimulation of the tongue T causes the tongue Tto move away from the soft palate SP, and stimulation of the back of thethroat causes the throat to move rearwardly. Alone or in combination,these actions increase the size of the airway thereby decreasing airvelocity and the disrupting force which would otherwise causeoscillation of the soft palate SP.

[0027] Stimulation of the muscles is accomplished by implantedelectrodes 10, 10′ and 10″ placed in the airway passage-defining muscles(identified above) of the soft palate SP, tongue T and back of throat(as illustrated in FIG. 6). Implantable muscle stimulating electrodesare well known and may be such as those used in cardiac pacing.

[0028] The implant 10, 10′, 10″ can be positioned and stimulated in aplurality of ways to alter the shape of the airway, to change thedynamic response of the airway tissues or a combination of both. Unlikethe prior art surgical techniques, the electrodes 10, 10′, 10″ that willbe described are easy to insert in a small incision resulting in reducedpatient discomfort and are not exposed to the interior of the mouth(such as the surface scarring of Huang, et al.) as a patient irritant.Also, as will be described, the degree of dynamic remodeling andstimulation pattern can be fine tuned avoiding the need for excessiveanatomical modification and are reversible in the event of adverseconsequences.

[0029] The present invention permits the surgeon to apply stimulation tovarious muscles until the desired alteration in airway area and tone isachieved so that snoring inducing oscillation is abated at normalairflow. The individual electrodes 10, 10′, 10″ may be placed into thesoft palate, tongue or throat muscles through small individual incisionsclosed by sutures which is much less traumatic than the gross anatomicaldestruction of uvulopalatopharyngoplasty or the large surface areascarring proposed by Huang, et al.

[0030] A control device 20 is provided for controlling the electrodes10, 10′, 10″ . The control device 20 is shown as a removable appliance(schematically shown in FIG. 6 with it being appreciated that appliancesfor placement in the mouth are well known) which fits the form of thehard palate or sub-lingual spaces.

[0031] The control device 20 is electrically coupled to the electrodes10, 10′, 10″ through electromagnetic coupling which avoids the need forelectrode leads being exposed from the implants 10, 10′, 10″.Specifically, the electrode 10 (shown in FIG. 7 and it being appreciatedthat electrodes 10′, 10″ are of similar construction) includes a pacingelectrode 12 for stimulating muscle in response to a signal through theelectrode 10. Leads 14 connect the pacing electrode 12 to an inductivewinding 16. In use, the entire electrode 10 (i.e., each of thecomponents of the pacing electrode 12, leads 14 and winding 16) areimbedded in the patient and not exposed.

[0032] The control device 20 is shown schematically and includes aninductive winding 22 connected to a control circuit 24. Control circuit24 is only shown schematically. Control circuits for pacing electrodesare well known and widely used in cardiac pacing. In the presentinvention, preferably none of the components of the control device 20(i.e., the winding 22 and circuit 24) are implanted. Instead, preferablysuch components are contained in the removable oral appliance controldevice 20 although some elements (e.g., a battery may be worn externallyby the patient).

[0033] The control winding 22 is positioned on the control device 20 tobe inductively coupled to the electrode winding 16 when the controldevice 20 is in place. In the event multiple electrodes 10, 10′, 10″ areplaced in multiple muscles, the control device 20 may contain aplurality of windings 22 each uniquely tuned to the windings of theelectrodes 10, 10′,10″ such that each electrode 10, 10′, 10″ may beuniquely paced. Also, each of the electrodes 10, 10′, 10″ can beprovided with filter circuits to pass only desired signals to the pacingelectrodes.

[0034] The control device 20 sends a pulsitile signal to the electrode10 through the inductive coupling of windings 16 and 22. In response,the electrode 10 causes pacing contraction of the muscle. Preferably,the pacing is selected to contract the muscle up to and includingtetanic contraction.

[0035] With the present invention, the muscle is contracted to increasethe size of the airway and reduce palatal flutter. The amount of pacingcan be tuned to the unique physiology of the patient. The control deviceneed only be used during sleep. It is anticipated that regular use ofthe control device 20 results in improved tone of the paced musclesreducing or eliminating future need to use the control device 20. Unlikethe appliances of U.S. Pat. Nos. 5,284,161 and 5,792,067, the presentdevice has more effective pacing since muscles are being paced directlyby implanted electrodes rather than through less efficient surfacestimulation. Further, the present invention contemplates pacing of allmuscles defining the airway passage and not just the soft palate.

[0036] Having described the invention, alternatives and embodiments mayoccur to one of skill in the art. It is intended that such modificationsand equivalents shall be included within the scope of the followingclaims.

What is claimed is:
 1. A method for treating snoring comprising:implanting a stimulating electrode into a patient with said electrode instimulating contact with an airway passage-controlling muscle of saidpatient; and energizing said electrode to contract said muscle and altersaid airway passage.
 2. A method according to claim 1 wherein saidelectrode is energized by electrically coupling said electrode throughan electromagnetic field to a controller not implanted in said patient.3. A method according to claim 2 wherein said controller is containedwith an appliance sized to be removably placed within a mouth cavity ofsaid patient and with said controller electrically coupled to saidelectrode when said appliance is placed within said mouth cavity.
 4. Amethod according to claim 1 wherein said muscle is a muscle of the softpalate.
 5. A method according to claim 1 wherein said muscle is a muscleof the tongue.
 6. A method according to claim 1 wherein said muscle is amuscle of the pharnyx.
 7. A method according to claim 4 wherein saidmuscle is selected from at least one of the Levator veli paltini, thePalatopharyngeous and the Palatoglossus muscles.
 8. A method accordingto claim 5 wherein said muscle is selected from at least one of theGenioglossus and Geniohyoid muscles.
 9. A method according to claim 6wherein said muscle is selected from at least one of the Superior,Middle and Inferior pharyngeal constrictor, the Salpingopharyngeous andthe Stylopharyngeous muscles.
 10. An apparatus for treating snoring of apatient, said apparatus comprising: a stimulating electrode adapted tobe implanted into a patient with said electrode in stimulating contactwith an airway passage-controlling muscle of said patient; and a controlmember for energizing said electrode to contract said muscle and altersaid airway passage.
 11. An apparatus according to claim 10 wherein saidelectrode and control member include cooperating components forinductively coupling said control member and said electrode.
 12. Anapparatus according to claim 11 wherein said control member is carriedon an appliance adapted to be removably placed, non-invasively in mouthof said patient.